1. Field
The disclosure relates to integrated circuit (IC) design, and more particularly, to techniques for designing a common-gate common-source amplifier.
2. Background
In transistor amplifier design, two commonly used circuit topologies are the common-gate amplifier and the common-source amplifier. Common-gate and common-source amplifiers may be used in the design of, e.g., low-noise amplifiers (LNA's) for radio-frequency integrated circuits (RFIC's). In a typical LNA design, a common-source amplifier may provide the advantage of good noise performance, but with the drawback of narrow input matching range. A common-gate amplifier, on the other hand, may provide the advantage of robust input matching, but with higher noise figure (NF).
Prior art techniques exist for unifying both the common-gate and common-source topologies in a single amplifier design. See, e.g., Blaakmeer, et al., “Wideband Balun-LNA With Simultaneous Output Balancing, Noise-Canceling and Distortion-Canceling,” IEEE Journal of Solid-State Circuits, Vol. 43, No. 6, June 2008, pp 1341-1350. It would be desirable to improve the performance of such unified common-gate common-source amplifiers, e.g., to decrease the noise figure of such amplifiers beyond what is available from the prior art.